Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!idt!vladan
From: vladan@idt.UUCP (Vladan Djakovic)
Newsgroups: comp.sys.mips
Subject: Re: Crash a RISC machine from user-mode code:
Summary: software vs. hardware
Keywords: RISC
Message-ID: <187@idt.UUCP>
Date: 20 Aug 90 23:23:15 GMT
References: <186@idt.UUCP> <1153@cluster.cs.su.oz>
Organization: IDT, Santa Clara
Lines: 22

In article <1153@cluster.cs.su.oz>, andrewt@cs.su.oz (Andrew Taylor) writes:
> Well giving the exact instructions and explanation of why it causes a panic
> seems very material to me. If you must see with your own eyes to be
> convinced try "./crashme 8 6710 1".

My mistake I did not make my comment and question more specific.

Sequence 0x07cb0d69, 0x46a7cc5d crashes the system due to the software
error. As noted, kernel makes mistake when preparing to return to user program
after processing illegal FP instruction exception. 
I also happen to know several other ways to crash MIPS UNIX from user mode
without any C programming. 
These are familiar everyday software errors.

I am interested if somebody managed to drive R[2|3]000 into undocumented
state by executing noise, as stated in the original posting. The kind of
state causing crash that cannot be prevented by a bug-free kernel.
-- 
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 # Vladan Djakovic, IDT (Integrated Device Technology), Santa Clara, CA     #
 #  ... uunet!idt!vladan      (All opinions are mine. Whose else?)          #
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